Tire pressure warning apparatus

ABSTRACT

A tire pressure warning apparatus for operation in a pneumatic tire in combination with an inner tube is disclosed. The warning apparatus comprises a pressure sensor, transmitter and a source of power sealingly adhered to an inner tube. The sensor assembly being in communication with the tire pressure for actuation of the transmitter in response to a drop in the tire pressure. Means are provided to protect the individual components while permitting the necessary flexibility to conform to the shape and motion of the inner surface of the tire.

fS tates" [191 Church Jan. 22, 1974 [54] TIRE PRESSURE WARNING APPARATUS3,593,269 7/1971 Richardson 340/58 [75] Inventor. Donald E. Church,Richmond, lnd. Primary Examiner Donald J Yusko [73] Assignee: AvcoCorporation, Richmond, lnd. Assistant Examiner-Joseph E. Nowicki [22]Filed: June 26 1972 ttgggyiglizgent, or Firm Charles M. l-logan, Eugene[21] App1.No.: 266,113

- [57] ABSTRACT [52] US. Cl 340/58, ZOO/61.22, 116/34 R, A tire Pregsurewarning apparatus for operation in a 73/14 3 73/14 5 pneumatic tire incombination with an inner tube is [51] Int. Cl. B600 23/04 disclosed-The warning apparatus comprises a Pressure [58] Field of Search 340/58,60, 237, 239; Sensor, transmitter and a source of power Sealingly 200/6122 6123 61.25 6126; 11 /34 R, hered to an inner tube. The sensorassembly being in 70; 73/1462 1463 14 5 communication with the tirepressure for actuation of r 3 v v v the transmitter in response to adrop in the tire pres- [56] R f i-" h Citd sure. Means are provided toprotect the individual i g UNITEI'DESTATE'SPATENTS componentswhilepermitting the necessary flexibility I r v to conform to the shapeand motion of the inner sur- 2,966,658 12/1960 ONeill.;..-.. .....'340/58, vface ofthe tire 3,281,784 10/1966 Farthing 340/58 3,533,063 4Claims, 6 Drawing Figures 10/1970 Garcia 340/58 PATENIED JAN 2 2 I974SHEET E BF 2 TIRE PRESSURE WARNING APPARATUS BACKGROUND OF THE INVENTIONThe present invention relates generally to pressure apparatus and moreparticularly to a tire pressure warning apparatus used in combinationwith an inner tube to provide warning of lowered pressures in tiresrequiring inner tubes.

Safe, efficient and economical transportation depends to a significantdegree on maintaining the correct pneumatic pressure in all tires of amotor vehicle. Failure to correct quickly a faulty air pressure mayresult in excessive tire wear, blow-outs, low gasoline mileage andsteering difficulties. Numerous tire warning systems are known in theart. Representative examples of such excesses may be found in US. Pat.Nos. 2,727,221 to Sprigg; 2,966,658 to ONeill; and 3,533,063 to Garcia.Truck tires differ from those used on personal cars in that inner tubesare generally used. While the prior art pressure warning systems can beutilized with tires utilizing inner tubes, quite often significantexpenses are involved to modify the tires to incorporate the prior artsystems. As an example, the sensor may be incorporated in the valve stemas is shown in Garcia and Sprigg. Often, substantial expense is requiredin providing the necessary modifications. To date, there is no tirepressure warning apparatus incorporated with an inner tube for use insuch systems.

Accordingly, it is an object of this invention to provide a tirepressure warning apparatus in combination with an inner tube for use ina system to provide indications of low tire pressure.

A further object of this invention is to provide a tire pressure warningapparatus having a configuration designed to be adhered to an innertube, the combination apparatus and inner tube fitting the inside of thetire.

sun'mavoms INVENTION "rms'isvsiiafipastas; 2; assistants warning ap sratus in combination with an inner tube for use in a vehicle tirepressure warning system. The pressure warning apparatus comprises asemi-flexible unit adhered to the inner tube. The unit embodies apressure sensor in communication with the tire pressure, a transmitter,and a source of power. The three elements are incorporated in an elasticmaterial to provide a flexible connection between each section toaccommodate for the flexing and distortion of the tire.

-Other objects, details, uses and advantages of this inembodiments ofthis invention in which:

FIG. I is a fragmentary top view of an inner tube with the warningapparatus secured thereto;

FIG. 2 is a sectional view taken on the line 22 of FIG. 1;

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 1;

FIG. 4 is a fragmentary top view of another embodiment of this inventionin which the warning apparatus is mounted inside the inner tube;

FIG. 5 is a sectional view taken along line 5-5 of FIG. 4; and

FIG. 6 is a sectional view taken along line 66 of FIG. 4.

DESCRIPTION OF ILLUSTRATED EMBODIMENTS 8 such as a hard plastic box. Thesensor 12 may be any vention will be apparent as the followingdescription of the exemplary embodiments thereof presented in theaccompanying drawings proceeds.

BRIEF DESCRIPTION or THE DRAWINGS The accompanying drawings show presentexemplary suitable pressure sensing device which provides a switchon/off action in response to pressure fluctuation outside apredetermined range. An example of such a sensor is described in aco-pending U. S. Pat. application of Brobeck and Lane, Ser. No. 237,386,filed Mar. 3, 1972, now US. Pat. No. 3,743,801 and owned by the assigneeof the present invention.

The source of power 16 may be any suitable battery, such as a mercurybattery. The battery 16 is housed in a suitable inflexible enclosure 22such as a hard plastic box or the like.

The transmitter 14 is housed in an inflexible enclosure 24 such as ahard plastic box or the like. Any suitable transmitter which willgenerate an RF signal may be used. An example of a suitable transmitteris a selfpulsed, squcgging Clapp oscillator 26 and a transmittingantenna 28. The oscillator 26 and antenna 28 are secured in the housing24 by any suitable potting material 30.

Appropriate leads 32 and 34 connect the sensor 12 with the batteryenclosure 22 and leads 36, 38 connect the battery enclosure 22 with thetransmitter 14. The leads 32, 34, 36 and 38 are formed using strandedwire. In addition, the wires are coiled to permit flexing of theapparatus 10 without incurring wire breakage. The sectionalizedapparatus 10, i.e., sensor 12, power supply 16, and transmitter 14 areencased in any suitable elastic material 40, such as natural rubber orthe like, to provide a flexibility comparable to that of the inner tube18. The semi-flexible warning apparatus 10 can be vulcanized, orotherwise adhered (hermetically sealed) to the top or crown of the innertube 18. The lead wires are molded in place in an area of minimumflexing. In the present embodiment, the inner tube 18 is provided withan aperture 42 therethrough to provide communication between the sensor12 and the internal tire pressure. To permit battery replacement, anysuitable insert 44 is secured in the elastic material 40. The insert 44is removable and cooperates with the enclosure 22 to 3 permit entry tothe enclosure 22. The enclosures 20, 22 and 24 are provided withappropriate terminals for connecting the respective leads with thecomponent elements.

The operation of the sensor 12 is fully described in the aforementionedapplication. It being sufficient herein to mention that the sensor 12incorporates a sealed pressurized dome which dimples when it is exposedto a pressure greater than a preselected minimum. The dimple provides anormally open snap switch which closes whenever the pneumatic pressurefalls below a value somewhat less than the pressure required to open theswitch. The operation of the snap switch by the sensor 12 completes thetransmitter 14 circuitry. The battery powered transmitter 14 generatesan RF signal which is picked up by any suitable receiver antenna mountedadjacent to the vehicle wheel. Any suitable communication link with thereceiving antenna will process the signal received from the transmitter14 to a suitable indicator generally mounted within the cab of thevehicle-wherein the indicator will communicate warning of low pressurein a tire to the operator of the motor vehicle.

Another exemplary embodiment of this invention is illustrated in FIGS.4-6 of the drawings. The tire pressure warning apparatus illustrated inFIGS. 4-6 is very similar to the apparatus therefore, such apparatuswill be designated generally by the reference numeral 10A and parts ofthe apparatus-10A which are very similar to the corresponding parts ofthe apparatus 10 will be designated by the same reference numeral as theapparatus 10 also followed by the letter designation A" and notdescribed again. The difference between the embodiment shown in FIGS.4-6 and the previously described embodiment is in the mounting of theapparatus relative to the inner tube. In the prior embodiment, theapparatus 10 is mounted exteriorly of the inner tube 18. ln the presentembodiment, the apparatus 10A is mounted to the inside of the inner tube18A. To accomplish this, a slot 46 is formed in the inner tube 18Athrough which the sembflexible unit 10A is inserted. The warningapparatus 10A is again vulcanized or otherwise adhered to the inside ofthe tube 18A so as to suitably seal the slot 46. The insert 44A permitsready access to the battery through the tube 18A and the elasticmaterial 40A. It is seen in this embodiment that the sensor 12A is indirect communication with the interior of the tube 18A. The elasticmaterial 40A is seen to have areas of reduced thickness between thesensor 12A, battery 16A and transmitter 14A. The reduced thicknessportions of the elastic material 40A readily permit flexing of thewarning apparatus 10A.

It can be seen that this invention provides a semiflexible tire pressurewarning apparatus used in combination with an inner tube. The individualcomponents of the apparatus are separately housed in hard enclosuresremote from each other, the components being entirely encased in anelastic material to permit relative flexing of the apparatus similarlyas the tire flexes or is deformed in use. Accordingly, the objectiveshereinbefore set forth have been accomplished.

While present exemplary embodiments of this invention have beenillustrated and described, it will be recognized that this invention maybe otherwise variously embodied and practiced by those skilled in theart.

What is claimed is:

-1. A vehicle tire pressure monitoring and warning apparatus adhered toan inner tube of a pneumatic tire for the pressure controlled generationof an RF signal comprising:

a pressure sensor exposed to the pneumatic pressure within the innertube;

a power supply;

a transmitter including a transmitting antenna;

said pressure sensor, power supply and transmitter configurated asseparate units;

flexible leads connecting said separate units; and

a flexible material surrounding each of said separate units, said unitsconfigurated to generate a single composite unit and to permit relativeflexing of each of said separate units relative to one another, saidflexible material being adhered to said inner tube and to conform inshape to the inner surface of the tire.

2. The warning apparatus as set forth in claim 1 in which each of saidsensor, power supply and transmitter is mounted in a hard container,each container being held by said flexible material.

3. The warning apparatus as set forth in claim 2 in which said flexiblematerial is secured to the exterior of the inner tube, the inner tubehaving an aperture therethrough opposite said sensor to providecommunication between said sensor and the interior of the inner tube.

4. The warning apparatus as set forth in claim 2 in which the warningapparatus is secured to the interior of the inner tube, said inner tubehaving an aperture therethrough opposite said power supply to provideaccess to said power supply; and a removable insert mounted in the innertube aperture.

1. A vehicle tire pressure monitoring and warning apparatus adhered toan inner tube of a pneumatic tire for the pressure controlled generationof an RF signal comprising: a pressure sensor exposed to the pneumaticpressure within the inner tube; a power supply; a transmitter includinga transmitting antenna; said pressure sensor, power supply andtransmitter configurated as separate units; flexible leads connectingsaid separate units; and a flexible material surrounding each of saidseparate units, said units configurated to generate a single compositeunit and to permit relative flexing of each of said separate unitsrelative to one another, said flexible material being adhered to saidinner tube and to conform in shape to the inner surface of the tire. 2.The warning apparatus as set forth in claim 1 in which each of saidsensor, power supply and transmitter is mounted in a hard container,each container being held by said flexible material.
 3. The warningapparatus aS set forth in claim 2 in which said flexible material issecured to the exterior of the inner tube, the inner tube having anaperture therethrough opposite said sensor to provide communicationbetween said sensor and the interior of the inner tube.
 4. The warningapparatus as set forth in claim 2 in which the warning apparatus issecured to the interior of the inner tube, said inner tube having anaperture therethrough opposite said power supply to provide access tosaid power supply; and a removable insert mounted in the inner tubeaperture.